forked from gliderlabs/sshfront
/
sshfront.go
88 lines (76 loc) · 1.89 KB
/
sshfront.go
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package main
import (
"flag"
"fmt"
"log"
"net"
"os"
"golang.org/x/crypto/ssh"
)
var Version string
var (
listenHost = flag.String("h", "0.0.0.0", "ip to listen on")
listenPort = flag.String("p", "22", "port to listen on")
hostKey = flag.String("k", "~/.ssh/id_rsa", "private host key path")
authHook = flag.String("a", "", "authentication hook. empty=allow all")
debugMode = flag.Bool("d", false, "debug mode")
useEnv = flag.Bool("e", false, "pass environment to handler")
)
func debug(v ...interface{}) {
if *debugMode {
log.Println(v...)
}
}
func handleConn(conn net.Conn, conf *ssh.ServerConfig) {
defer conn.Close()
sshConn, chans, reqs, err := ssh.NewServerConn(conn, conf)
if err != nil {
debug("handshake failed:", err)
return
}
go ssh.DiscardRequests(reqs)
for ch := range chans {
if ch.ChannelType() != "session" {
ch.Reject(ssh.UnknownChannelType, "unsupported channel type")
debug("channel rejected, unsupported type:", ch.ChannelType())
continue
}
go handleChannel(sshConn, ch)
}
}
func init() {
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "Usage: %v [options] <handler>\n\n", os.Args[0])
flag.PrintDefaults()
}
}
func main() {
flag.Parse()
if flag.NArg() < 1 {
flag.Usage()
os.Exit(64)
}
config := &ssh.ServerConfig{
PublicKeyCallback: func(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
return handleAuth(conn, key)
},
}
setupHostKey(config)
var listenAddr string
if listenAddr = os.Getenv("SSHFRONT_LISTEN"); listenAddr == "" {
listenAddr = fmt.Sprintf("%s:%s", *listenHost, *listenPort)
}
log.Printf("sshfront v%s listening on %s ...\n", Version, listenAddr)
listener, err := net.Listen("tcp", listenAddr)
if err != nil {
log.Fatalln("listen failed:", err)
}
for {
conn, err := listener.Accept()
if err != nil {
debug("accept failed:", err)
continue
}
go handleConn(conn, config)
}
}